/*
* Internal header for libusb
* Copyright © 2007-2009 Daniel Drake <dsd@gentoo.org>
* Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
* Copyright © 2019 Nathan Hjelm <hjelmn@cs.umm.edu>
* Copyright © 2019 Google LLC. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef LIBUSBI_H
#define LIBUSBI_H
#include <config.h>
#include <stdlib.h>
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <time.h>
#include <stdarg.h>
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#ifdef HAVE_MISSING_H
#include <missing.h>
#endif
#include "libusb.h"
#include "version.h"
/* Attribute to ensure that a structure member is aligned to a natural
* pointer alignment. Used for os_priv member. */
#if defined(_MSC_VER)
#if defined(_WIN64)
#define PTR_ALIGNED __declspec(align(8))
#else
#define PTR_ALIGNED __declspec(align(4))
#endif
#elif defined(__GNUC__) && (__GNUC__ >= 3)
#define PTR_ALIGNED __attribute__((aligned(sizeof(void *))))
#else
#define PTR_ALIGNED
#endif
/* Inside the libusb code, mark all public functions as follows:
* return_type API_EXPORTED function_name(params) { ... }
* But if the function returns a pointer, mark it as follows:
* DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... }
* In the libusb public header, mark all declarations as:
* return_type LIBUSB_CALL function_name(params);
*/
#define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY
/* Macro to decorate printf-like functions, in order to get
* compiler warnings about format string mistakes.
*/
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2)
#define USBI_PRINTFLIKE(formatarg, firstvararg) \
__attribute__((__format__ (__printf__, formatarg, firstvararg)))
#else
#define USBI_PRINTFLIKE(formatarg, firstvararg)
#endif
#ifdef __cplusplus
extern "C" {
#endif
#define DEVICE_DESC_LENGTH 18
#define USB_MAXENDPOINTS 32
#define USB_MAXINTERFACES 32
#define USB_MAXCONFIG 8
/* Backend specific capabilities */
#define USBI_CAP_HAS_HID_ACCESS 0x00010000
#define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
/* Maximum number of bytes in a log line */
#define USBI_MAX_LOG_LEN 1024
/* Terminator for log lines */
#define USBI_LOG_LINE_END "\n"
/* The following is used to silence warnings for unused variables */
#define UNUSED(var) do { (void)(var); } while(0)
#if !defined(ARRAYSIZE)
#define ARRAYSIZE(array) (sizeof(array) / sizeof(array[0]))
#endif
struct list_head {
struct list_head *prev, *next;
};
/* Get an entry from the list
* ptr - the address of this list_head element in "type"
* type - the data type that contains "member"
* member - the list_head element in "type"
*/
#define list_entry(ptr, type, member) \
((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member)))
#define list_first_entry(ptr, type, member) \
list_entry((ptr)->next, type, member)
/* Get each entry from a list
* pos - A structure pointer has a "member" element
* head - list head
* member - the list_head element in "pos"
* type - the type of the first parameter
*/
#define list_for_each_entry(pos, head, member, type) \
for (pos = list_entry((head)->next, type, member); \
&pos->member != (head); \
pos = list_entry(pos->member.next, type, member))
#define list_for_each_entry_safe(pos, n, head, member, type) \
for (pos = list_entry((head)->next, type, member), \
n = list_entry(pos->member.next, type, member); \
&pos->member != (head); \
pos = n, n = list_entry(n->member.next, type, member))
#define list_empty(entry) ((entry)->next == (entry))
static inline void list_init(struct list_head *entry)
{
entry->prev = entry->next = entry;
}
static inline void list_add(struct list_head *entry, struct list_head *head)
{
entry->next = head->next;
entry->prev = head;
head->next->prev = entry;
head->next = entry;
}
static inline void list_add_tail(struct list_head *entry,
struct list_head *head)
{
entry->next = head;
entry->prev = head->prev;
head->prev->next = entry;
head->prev = entry;
}
static inline void list_del(struct list_head *entry)
{
entry->next->prev = entry->prev;
entry->prev->next = entry->next;
entry->next = entry->prev = NULL;
}
static inline void list_cut(struct list_head *list, struct list_head *head)
{
if (list_empty(head))
return;
list->next = head->next;
list->next->prev = list;
list->prev = head->prev;
list->prev->next = list;
list_init(head);
}
static inline void *usbi_reallocf(void *ptr, size_t size)
{
void *ret = realloc(ptr, size);
if (!ret)
free(ptr);
return ret;
}
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *mptr = (ptr); \
(type *)( (char *)mptr - offsetof(type,member) );})
#ifndef CLAMP
#define CLAMP(val, min, max) ((val) < (min) ? (min) : ((val) > (max) ? (max) : (val)))
#endif
#ifndef MIN
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
#ifndef MAX
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#endif
#define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
#if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
#define TIMEVAL_TV_SEC_TYPE long
#else
#define TIMEVAL_TV_SEC_TYPE time_t
#endif
/* Some platforms don't have this define */
#ifndef TIMESPEC_TO_TIMEVAL
#define TIMESPEC_TO_TIMEVAL(tv, ts) \
do { \
(tv)->tv_sec = (TIMEVAL_TV_SEC_TYPE) (ts)->tv_sec; \
(tv)->tv_usec = (ts)->tv_nsec / 1000; \
} while (0)
#endif
#ifdef ENABLE_LOGGING
#if defined(_MSC_VER) && (_MSC_VER < 1900)
#define snprintf usbi_snprintf
#define vsnprintf usbi_vsnprintf
int usbi_snprintf(char *dst, size_t size, const char *format, ...);
int usbi_vsnprintf(char *dst, size_t size, const char *format, va_list ap);
#define LIBUSB_PRINTF_WIN32
#endif /* defined(_MSC_VER) && (_MSC_VER < 1900) */
void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
const char *function, const char *format, ...) USBI_PRINTFLIKE(4, 5);
void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
const char *function, const char *format, va_list args) USBI_PRINTFLIKE(4, 0);
#if !defined(_MSC_VER) || (_MSC_VER >= 1400)
#define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
#define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__)
#define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__)
#define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__)
#define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__)
#else /* !defined(_MSC_VER) || (_MSC_VER >= 1400) */
#define LOG_BODY(ctxt, level) \
{ \
va_list args; \
va_start(args, format); \
usbi_log_v(ctxt, level, "", format, args); \
va_end(args); \
}
static inline void usbi_err(struct libusb_context *ctx, const char *format, ...)
LOG_BODY(ctx, LIBUSB_LOG_LEVEL_ERROR)
static inline void usbi_warn(struct libusb_context *ctx, const char *format, ...)
LOG_BODY(ctx, LIBUSB_LOG_LEVEL_WARNING)
static inline void usbi_info(struct libusb_context *ctx, const char *format, ...)
LOG_BODY(ctx, LIBUSB_LOG_LEVEL_INFO)
static inline void usbi_dbg(const char *format, ...)
LOG_BODY(NULL, LIBUSB_LOG_LEVEL_DEBUG)
#endif /* !defined(_MSC_VER) || (_MSC_VER >= 1400) */
#else /* ENABLE_LOGGING */
#define usbi_err(ctx, ...) do { (void)ctx; } while (0)
#define usbi_warn(ctx, ...) do { (void)ctx; } while (0)
#define usbi_info(ctx, ...) do { (void)ctx; } while (0)
#define usbi_dbg(...) do {} while (0)
#endif /* ENABLE_LOGGING */
#define USBI_GET_CONTEXT(ctx) \
do { \
if (!(ctx)) \
(ctx) = usbi_default_context; \
} while(0)
#define DEVICE_CTX(dev) ((dev)->ctx)
#define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
#define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
#define ITRANSFER_CTX(transfer) \
(TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
#define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN))
#define IS_EPOUT(ep) (!IS_EPIN(ep))
#define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN))
#define IS_XFEROUT(xfer) (!IS_XFERIN(xfer))
/* Internal abstraction for thread synchronization */
#if defined(THREADS_POSIX)
#include "os/threads_posix.h"
#elif defined(OS_WINDOWS) || defined(OS_WINCE)
#include "os/threads_windows.h"
#endif
extern struct libusb_context *usbi_default_context;
/* Forward declaration for use in context (fully defined inside poll abstraction) */
struct pollfd;
struct libusb_context {
#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
enum libusb_log_level debug;
int debug_fixed;
libusb_log_cb log_handler;
#endif
/* internal event pipe, used for signalling occurrence of an internal event. */
int event_pipe[2];
struct list_head usb_devs;
usbi_mutex_t usb_devs_lock;
/* A list of open handles. Backends are free to traverse this if required.
*/
struct list_head open_devs;
usbi_mutex_t open_devs_lock;
/* A list of registered hotplug callbacks */
struct list_head hotplug_cbs;
libusb_hotplug_callback_handle next_hotplug_cb_handle;
usbi_mutex_t hotplug_cbs_lock;
/* this is a list of in-flight transfer handles, sorted by timeout
* expiration. URBs to timeout the soonest are placed at the beginning of
* the list, URBs that will time out later are placed after, and urbs with
* infinite timeout are always placed at the very end. */
struct list_head flying_transfers;
/* Note paths taking both this and usbi_transfer->lock must always
* take this lock first */
usbi_mutex_t flying_transfers_lock;
/* user callbacks for pollfd changes */
libusb_pollfd_added_cb fd_added_cb;
libusb_pollfd_removed_cb fd_removed_cb;
void *fd_cb_user_data;
/* ensures that only one thread is handling events at any one time */
usbi_mutex_t events_lock;
/* used to see if there is an active thread doing event handling */
int event_handler_active;
/* A thread-local storage key to track which thread is performing event
* handling */
usbi_tls_key_t event_handling_key;
/* used to wait for event completion in threads other than the one that is
* event handling */
usbi_mutex_t event_waiters_lock;
usbi_cond_t event_waiters_cond;
/* A lock to protect internal context event data. */
usbi_mutex_t event_data_lock;
/* A bitmask of flags that are set to indicate specific events that need to
* be handled. Protected by event_data_lock. */
unsigned int event_flags;
/* A counter that is set when we want to interrupt and prevent event handling,
* in order to safely close a device. Protected by event_data_lock. */
unsigned int device_close;
/* list and count of poll fds and an array of poll fd structures that is
* (re)allocated as necessary prior to polling. Protected by event_data_lock. */
struct list_head ipollfds;
/* list of pollfds that have been removed. keeps track of pollfd changes
* between the poll call and */
struct list_head removed_ipollfds;
struct pollfd *pollfds;
POLL_NFDS_TYPE pollfds_cnt;
/* A list of pending hotplug messages. Protected by event_data_lock. */
struct list_head hotplug_msgs;
/* A list of pending completed transfers. Protected by event_data_lock. */
struct list_head completed_transfers;
#ifdef USBI_TIMERFD_AVAILABLE
/* used for timeout handling, if supported by OS.
* this timerfd is maintained to trigger on the next pending timeout */
int timerfd;
#endif
struct list_head list;
PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
};
enum usbi_event_flags {
/* The list of pollfds has been modified */
USBI_EVENT_POLLFDS_MODIFIED = 1U << 0,
/* The user has interrupted the event handler */
USBI_EVENT_USER_INTERRUPT = 1U << 1,
/* A hotplug callback deregistration is pending */
USBI_EVENT_HOTPLUG_CB_DEREGISTERED = 1U << 2,
};
/* Macros for managing event handling state */
#define usbi_handling_events(ctx) \
(usbi_tls_key_get((ctx)->event_handling_key) != NULL)
#define usbi_start_event_handling(ctx) \
usbi_tls_key_set((ctx)->event_handling_key, ctx)
#define usbi_end_event_handling(ctx) \
usbi_tls_key_set((ctx)->event_handling_key, NULL)
/* Update the following macro if new event sources are added */
#define usbi_pending_events(ctx) \
((ctx)->event_flags || (ctx)->device_close \
|| !list_empty(&(ctx)->hotplug_msgs) || !list_empty(&(ctx)->completed_transfers))
#ifdef USBI_TIMERFD_AVAILABLE
#define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
#else
#define usbi_using_timerfd(ctx) (0)
#endif
struct libusb_device {
/* lock protects refcnt, everything else is finalized at initialization
* time */
usbi_mutex_t lock;
int refcnt;
struct libusb_context *ctx;
uint8_t bus_number;
uint8_t port_number;
struct libusb_device* parent_dev;
uint8_t device_address;
uint8_t num_configurations;
enum libusb_speed speed;
struct list_head list;
unsigned long session_data;
struct libusb_device_descriptor device_descriptor;
int attached;
PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
};
struct libusb_device_handle {
/* lock protects claimed_interfaces */
usbi_mutex_t lock;
unsigned long claimed_interfaces;
struct list_head list;
struct libusb_device *dev;
int auto_detach_kernel_driver;
PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
};
enum {
USBI_CLOCK_MONOTONIC,
USBI_CLOCK_REALTIME
};
/* in-memory transfer layout:
*
* 1. struct usbi_transfer
* 2. struct libusb_transfer (which includes iso packets) [variable size]
* 3. os private data [variable size]
*
* from a libusb_transfer, you can get the usbi_transfer by rewinding the
* appropriate number of bytes.
* the usbi_transfer includes the number of allocated packets, so you can
* determine the size of the transfer and hence the start and length of the
* OS-private data.
*/
struct usbi_transfer {
int num_iso_packets;
struct list_head list;
struct list_head completed_list;
struct timeval timeout;
int transferred;
uint32_t stream_id;
uint8_t state_flags; /* Protected by usbi_transfer->lock */
uint8_t timeout_flags; /* Protected by the flying_stransfers_lock */
/* this lock is held during libusb_submit_transfer() and
* libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
* cancellation, submission-during-cancellation, etc). the OS backend
* should also take this lock in the handle_events path, to prevent the user
* cancelling the transfer from another thread while you are processing
* its completion (presumably there would be races within your OS backend
* if this were possible).
* Note paths taking both this and the flying_transfers_lock must
* always take the flying_transfers_lock first */
usbi_mutex_t lock;
};
enum usbi_transfer_state_flags {
/* Transfer successfully submitted by backend */
USBI_TRANSFER_IN_FLIGHT = 1U << 0,
/* Cancellation was requested via libusb_cancel_transfer() */
USBI_TRANSFER_CANCELLING = 1U << 1,
/* Operation on the transfer failed because the device disappeared */
USBI_TRANSFER_DEVICE_DISAPPEARED = 1U << 2,
};
enum usbi_transfer_timeout_flags {
/* Set by backend submit_transfer() if the OS handles timeout */
USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1U << 0,
/* The transfer timeout has been handled */
USBI_TRANSFER_TIMEOUT_HANDLED = 1U << 1,
/* The transfer timeout was successfully processed */
USBI_TRANSFER_TIMED_OUT = 1U << 2,
};
#define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
((struct libusb_transfer *)(((unsigned char *)(transfer)) \
+ sizeof(struct usbi_transfer)))
#define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
((struct usbi_transfer *)(((unsigned char *)(transfer)) \
- sizeof(struct usbi_transfer)))
static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
{
assert(transfer->num_iso_packets >= 0);
return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
+ sizeof(struct libusb_transfer)
+ ((size_t)transfer->num_iso_packets
* sizeof(struct libusb_iso_packet_descriptor));
}
/* bus structures */
/* All standard descriptors have these 2 fields in common */
struct usb_descriptor_header {
uint8_t bLength;
uint8_t bDescriptorType;
};
/* shared data and functions */
int usbi_io_init(struct libusb_context *ctx);
void usbi_io_exit(struct libusb_context *ctx);
struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
unsigned long session_id);
struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
unsigned long session_id);
int usbi_sanitize_device(struct libusb_device *dev);
void usbi_handle_disconnect(struct libusb_device_handle *dev_handle);
int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
enum libusb_transfer_status status);
int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
void usbi_signal_transfer_completion(struct usbi_transfer *transfer);
int usbi_parse_descriptor(const unsigned char *source, const char *descriptor,
void *dest, int host_endian);
int usbi_device_cache_descriptor(libusb_device *dev);
int usbi_get_config_index_by_value(struct libusb_device *dev,
uint8_t bConfigurationValue, int *idx);
void usbi_connect_device (struct libusb_device *dev);
void usbi_disconnect_device (struct libusb_device *dev);
int usbi_signal_event(struct libusb_context *ctx);
int usbi_clear_event(struct libusb_context *ctx);
/* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
#if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD) || defined(OS_NETBSD) ||\
defined(OS_HAIKU) || defined(OS_SUNOS) || defined(OS_NULL)
#include <unistd.h>
#include "os/poll_posix.h"
#elif defined(OS_WINDOWS) || defined(OS_WINCE)
#include "os/poll_windows.h"
#endif
struct usbi_pollfd {
/* must come first */
struct libusb_pollfd pollfd;
struct list_head list;
};
int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
/* device discovery */
/* we traverse usbfs without knowing how many devices we are going to find.
* so we create this discovered_devs model which is similar to a linked-list
* which grows when required. it can be freed once discovery has completed,
* eliminating the need for a list node in the libusb_device structure
* itself. */
struct discovered_devs {
size_t len;
size_t capacity;
struct libusb_device *devices[ZERO_SIZED_ARRAY];
};
struct discovered_devs *discovered_devs_append(
struct discovered_devs *discdevs, struct libusb_device *dev);
/* OS abstraction */
/* This is the interface that OS backends need to implement.
* All fields are mandatory, except ones explicitly noted as optional. */
struct usbi_os_backend {
/* A human-readable name for your backend, e.g. "Linux usbfs" */
const char *name;
/* Binary mask for backend specific capabilities */
uint32_t caps;
/* Perform initialization of your backend. You might use this function
* to determine specific capabilities of the system, allocate required
* data structures for later, etc.
*
* This function is called when a libusb user initializes the library
* prior to use.
*
* Return 0 on success, or a LIBUSB_ERROR code on failure.
*/
int (*init)(struct libusb_context *ctx);
/* Deinitialization. Optional. This function should destroy anything
* that was set up by init.
*
* This function is called when the user deinitializes the library.
*/
void (*exit)(struct libusb_context *ctx);
/* Set a backend-specific option. Optional.
*
* This function is called when the user calls libusb_set_option() and
* the option is not handled by the core library.
*
* Return 0 on success, or a LIBUSB_ERROR code on failure.
*/
int (*set_option)(struct libusb_context *ctx, enum libusb_option option,
va_list args);
/* Enumerate all the USB devices on the system, returning them in a list
* of discovered devices.
*
* Your implementation should enumerate all devices on the system,
* regardless of whether they have been seen before or not.
*
* When you have found a device, compute a session ID for it. The session
* ID should uniquely represent that particular device for that particular
* connection session since boot (i.e. if you disconnect and reconnect a
* device immediately after, it should be assigned a different session ID).
* If your OS cannot provide a unique session ID as described above,
* presenting a session ID of (bus_number << 8 | device_address) should
* be sufficient. Bus numbers and device addresses wrap and get reused,
* but that is an unlikely case.
*
* After computing a session ID for a device, call
* usbi_get_device_by_session_id(). This function checks if libusb already
* knows about the device, and if so, it provides you with a reference
* to a libusb_device structure for it.
*
* If usbi_get_device_by_session_id() returns NULL, it is time to allocate
* a new device structure for the device. Call usbi_alloc_device() to
* obtain a new libusb_device structure with reference count 1. Populate
* the bus_number and device_address attributes of the new device, and
* perform any other internal backend initialization you need to do. At
* this point, you should be ready to provide device descriptors and so
* on through the get_*_descriptor functions. Finally, call
* usbi_sanitize_device() to perform some final sanity checks on the
* device. Assuming all of the above succeeded, we can now continue.
* If any of the above failed, remember to unreference the device that
* was returned by usbi_alloc_device().
*
* At this stage we have a populated libusb_device structure (either one
* that was found earlier, or one that we have just allocated and
* populated). This can now be added to the discovered devices list
* using discovered_devs_append(). Note that discovered_devs_append()
* may reallocate the list, returning a new location for it, and also
* note that reallocation can fail. Your backend should handle these
* error conditions appropriately.
*
* This function should not generate any bus I/O and should not block.
* If I/O is required (e.g. reading the active configuration value), it is
* OK to ignore these suggestions :)
*
* This function is executed when the user wishes to retrieve a list
* of USB devices connected to the system.
*
* If the backend has hotplug support, this function is not used!
*
* Return 0 on success, or a LIBUSB_ERROR code on failure.
*/
int (*get_device_list)(struct libusb_context *ctx,
struct discovered_devs **discdevs);
/* Apps which were written before hotplug support, may listen for
* hotplug events on their own and call libusb_get_device_list on
* device addition. In this case libusb_get_device_list will likely
* return a list without the new device in there, as the hotplug
* event thread will still be busy enumerating the device, which may
* take a while, or may not even have seen the event yet.
*
* To avoid this libusb_get_device_list will call this optional
* function for backends with hotplug support before copying
* ctx->usb_devs to the user. In this function the backend should
* ensure any pending hotplug events are fully processed before
* returning.
*
* Optional, should be implemented by backends with hotplug support.
*/
void (*hotplug_poll)(void);
/* Wrap a platform-specific device handle for I/O and other USB
* operations. The device handle is preallocated for you.
*
* Your backend should allocate any internal resources required for I/O
* and other operations so that those operations can happen (hopefully)
* without hiccup. This is also a good place to inform libusb that it
* should monitor certain file descriptors related to this device -
* see the usbi_add_pollfd() function.
*
* Your backend should also initialize the device structure
* (dev_handle->dev), which is NULL at the beginning of the call.
*
* This function should not generate any bus I/O and should not block.
*
* This function is called when the user attempts to wrap an existing
* platform-specific device handle for a device.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
* - another LIBUSB_ERROR code on other failure
*
* Do not worry about freeing the handle on failed open, the upper layers
* do this for you.
*/
int (*wrap_sys_device)(struct libusb_context *ctx,
struct libusb_device_handle *dev_handle, intptr_t sys_dev);
/* Open a device for I/O and other USB operations. The device handle
* is preallocated for you, you can retrieve the device in question
* through handle->dev.
*
* Your backend should allocate any internal resources required for I/O
* and other operations so that those operations can happen (hopefully)
* without hiccup. This is also a good place to inform libusb that it
* should monitor certain file descriptors related to this device -
* see the usbi_add_pollfd() function.
*
* This function should not generate any bus I/O and should not block.
*
* This function is called when the user attempts to obtain a device
* handle for a device.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
* discovery
* - another LIBUSB_ERROR code on other failure
*
* Do not worry about freeing the handle on failed open, the upper layers
* do this for you.
*/
int (*open)(struct libusb_device_handle *dev_handle);
/* Close a device such that the handle cannot be used again. Your backend
* should destroy any resources that were allocated in the open path.
* This may also be a good place to call usbi_remove_pollfd() to inform
* libusb of any file descriptors associated with this device that should
* no longer be monitored.
*
* This function is called when the user closes a device handle.
*/
void (*close)(struct libusb_device_handle *dev_handle);
/* Retrieve the device descriptor from a device.
*
* The descriptor should be retrieved from memory, NOT via bus I/O to the
* device. This means that you may have to cache it in a private structure
* during get_device_list enumeration. Alternatively, you may be able
* to retrieve it from a kernel interface (some Linux setups can do this)
* still without generating bus I/O.
*
* This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
* buffer, which is guaranteed to be big enough.
*
* This function is called when sanity-checking a device before adding
* it to the list of discovered devices, and also when the user requests
* to read the device descriptor.
*
* This function is expected to return the descriptor in bus-endian format
* (LE). If it returns the multi-byte values in host-endian format,
* set the host_endian output parameter to "1".
*
* Return 0 on success or a LIBUSB_ERROR code on failure.
*/
int (*get_device_descriptor)(struct libusb_device *device,
unsigned char *buffer, int *host_endian);
/* Get the ACTIVE configuration descriptor for a device.
*
* The descriptor should be retrieved from memory, NOT via bus I/O to the
* device. This means that you may have to cache it in a private structure
* during get_device_list enumeration. You may also have to keep track
* of which configuration is active when the user changes it.
*
* This function is expected to write len bytes of data into buffer, which
* is guaranteed to be big enough. If you can only do a partial write,
* return an error code.
*
* This function is expected to return the descriptor in bus-endian format
* (LE). If it returns the multi-byte values in host-endian format,
* set the host_endian output parameter to "1".
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
* - another LIBUSB_ERROR code on other failure
*/
int (*get_active_config_descriptor)(struct libusb_device *device,
unsigned char *buffer, size_t len, int *host_endian);
/* Get a specific configuration descriptor for a device.
*
* The descriptor should be retrieved from memory, NOT via bus I/O to the
* device. This means that you may have to cache it in a private structure
* during get_device_list enumeration.
*
* The requested descriptor is expressed as a zero-based index (i.e. 0
* indicates that we are requesting the first descriptor). The index does
* not (necessarily) equal the bConfigurationValue of the configuration
* being requested.
*
* This function is expected to write len bytes of data into buffer, which
* is guaranteed to be big enough. If you can only do a partial write,
* return an error code.
*
* This function is expected to return the descriptor in bus-endian format
* (LE). If it returns the multi-byte values in host-endian format,
* set the host_endian output parameter to "1".
*
* Return the length read on success or a LIBUSB_ERROR code on failure.
*/
int (*get_config_descriptor)(struct libusb_device *device,
uint8_t config_index, unsigned char *buffer, size_t len,
int *host_endian);
/* Like get_config_descriptor but then by bConfigurationValue instead
* of by index.
*
* Optional, if not present the core will call get_config_descriptor
* for all configs until it finds the desired bConfigurationValue.
*
* Returns a pointer to the raw-descriptor in *buffer, this memory
* is valid as long as device is valid.
*
* Returns the length of the returned raw-descriptor on success,
* or a LIBUSB_ERROR code on failure.
*/
int (*get_config_descriptor_by_value)(struct libusb_device *device,
uint8_t bConfigurationValue, unsigned char **buffer,
int *host_endian);
/* Get the bConfigurationValue for the active configuration for a device.
* Optional. This should only be implemented if you can retrieve it from
* cache (don't generate I/O).
*
* If you cannot retrieve this from cache, either do not implement this
* function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
* libusb to retrieve the information through a standard control transfer.
*
* This function must be non-blocking.
* Return:
* - 0 on success
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
* blocking
* - another LIBUSB_ERROR code on other failure.
*/
int (*get_configuration)(struct libusb_device_handle *dev_handle, int *config);
/* Set the active configuration for a device.
*
* A configuration value of -1 should put the device in unconfigured state.
*
* This function can block.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
* - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
* configuration cannot be changed)
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure.
*/
int (*set_configuration)(struct libusb_device_handle *dev_handle, int config);
/* Claim an interface. When claimed, the application can then perform
* I/O to an interface's endpoints.
*
* This function should not generate any bus I/O and should not block.
* Interface claiming is a logical operation that simply ensures that
* no other drivers/applications are using the interface, and after
* claiming, no other drivers/applications can use the interface because
* we now "own" it.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
* - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*claim_interface)(struct libusb_device_handle *dev_handle, int interface_number);
/* Release a previously claimed interface.
*
* This function should also generate a SET_INTERFACE control request,
* resetting the alternate setting of that interface to 0. It's OK for
* this function to block as a result.
*
* You will only ever be asked to release an interface which was
* successfully claimed earlier.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*release_interface)(struct libusb_device_handle *dev_handle, int interface_number);
/* Set the alternate setting for an interface.
*
* You will only ever be asked to set the alternate setting for an
* interface which was successfully claimed earlier.
*
* It's OK for this function to block.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*set_interface_altsetting)(struct libusb_device_handle *dev_handle,
int interface_number, int altsetting);
/* Clear a halt/stall condition on an endpoint.
*
* It's OK for this function to block.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*clear_halt)(struct libusb_device_handle *dev_handle,
unsigned char endpoint);
/* Perform a USB port reset to reinitialize a device.
*
* If possible, the device handle should still be usable after the reset
* completes, assuming that the device descriptors did not change during
* reset and all previous interface state can be restored.
*
* If something changes, or you cannot easily locate/verify the resetted
* device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
* to close the old handle and re-enumerate the device.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
* has been disconnected since it was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*reset_device)(struct libusb_device_handle *dev_handle);
/* Alloc num_streams usb3 bulk streams on the passed in endpoints */
int (*alloc_streams)(struct libusb_device_handle *dev_handle,
uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
/* Free usb3 bulk streams allocated with alloc_streams */
int (*free_streams)(struct libusb_device_handle *dev_handle,
unsigned char *endpoints, int num_endpoints);
/* Allocate persistent DMA memory for the given device, suitable for
* zerocopy. May return NULL on failure. Optional to implement.
*/
unsigned char *(*dev_mem_alloc)(struct libusb_device_handle *handle,
size_t len);
/* Free memory allocated by dev_mem_alloc. */
int (*dev_mem_free)(struct libusb_device_handle *handle,
unsigned char *buffer, size_t len);
/* Determine if a kernel driver is active on an interface. Optional.
*
* The presence of a kernel driver on an interface indicates that any
* calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
*
* Return:
* - 0 if no driver is active
* - 1 if a driver is active
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*kernel_driver_active)(struct libusb_device_handle *dev_handle,
int interface_number);
/* Detach a kernel driver from an interface. Optional.
*
* After detaching a kernel driver, the interface should be available
* for claim.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
* - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - another LIBUSB_ERROR code on other failure
*/
int (*detach_kernel_driver)(struct libusb_device_handle *dev_handle,
int interface_number);
/* Attach a kernel driver to an interface. Optional.
*
* Reattach a kernel driver to the device.
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
* - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
* was opened
* - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
* preventing reattachment
* - another LIBUSB_ERROR code on other failure
*/
int (*attach_kernel_driver)(struct libusb_device_handle *dev_handle,
int interface_number);
/* Destroy a device. Optional.
*
* This function is called when the last reference to a device is
* destroyed. It should free any resources allocated in the get_device_list
* path.
*/
void (*destroy_device)(struct libusb_device *dev);
/* Submit a transfer. Your implementation should take the transfer,
* morph it into whatever form your platform requires, and submit it
* asynchronously.
*
* This function must not block.
*
* This function gets called with the flying_transfers_lock locked!
*
* Return:
* - 0 on success
* - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
* - another LIBUSB_ERROR code on other failure
*/
int (*submit_transfer)(struct usbi_transfer *itransfer);
/* Cancel a previously submitted transfer.
*
* This function must not block. The transfer cancellation must complete
* later, resulting in a call to usbi_handle_transfer_cancellation()
* from the context of handle_events.
*/
int (*cancel_transfer)(struct usbi_transfer *itransfer);
/* Clear a transfer as if it has completed or cancelled, but do not
* report any completion/cancellation to the library. You should free
* all private data from the transfer as if you were just about to report
* completion or cancellation.
*
* This function might seem a bit out of place. It is used when libusb
* detects a disconnected device - it calls this function for all pending
* transfers before reporting completion (with the disconnect code) to
* the user. Maybe we can improve upon this internal interface in future.
*/
void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
/* Handle any pending events on file descriptors. Optional.
*
* Provide this function when file descriptors directly indicate device
* or transfer activity. If your backend does not have such file descriptors,
* implement the handle_transfer_completion function below.
*
* This involves monitoring any active transfers and processing their
* completion or cancellation.
*
* The function is passed an array of pollfd structures (size nfds)
* as a result of the poll() system call. The num_ready parameter
* indicates the number of file descriptors that have reported events
* (i.e. the poll() return value). This should be enough information
* for you to determine which actions need to be taken on the currently
* active transfers.
*
* For any cancelled transfers, call usbi_handle_transfer_cancellation().
* For completed transfers, call usbi_handle_transfer_completion().
* For control/bulk/interrupt transfers, populate the "transferred"
* element of the appropriate usbi_transfer structure before calling the
* above functions. For isochronous transfers, populate the status and
* transferred fields of the iso packet descriptors of the transfer.
*
* This function should also be able to detect disconnection of the
* device, reporting that situation with usbi_handle_disconnect().
*
* When processing an event related to a transfer, you probably want to
* take usbi_transfer.lock to prevent races. See the documentation for
* the usbi_transfer structure.
*
* Return 0 on success, or a LIBUSB_ERROR code on failure.
*/
int (*handle_events)(struct libusb_context *ctx,
struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready);
/* Handle transfer completion. Optional.
*
* Provide this function when there are no file descriptors available
* that directly indicate device or transfer activity. If your backend does
* have such file descriptors, implement the handle_events function above.
*
* Your backend must tell the library when a transfer has completed by
* calling usbi_signal_transfer_completion(). You should store any private
* information about the transfer and its completion status in the transfer's
* private backend data.
*
* During event handling, this function will be called on each transfer for
* which usbi_signal_transfer_completion() was called.
*
* For any cancelled transfers, call usbi_handle_transfer_cancellation().
* For completed transfers, call usbi_handle_transfer_completion().
* For control/bulk/interrupt transfers, populate the "transferred"
* element of the appropriate usbi_transfer structure before calling the
* above functions. For isochronous transfers, populate the status and
* transferred fields of the iso packet descriptors of the transfer.
*
* Return 0 on success, or a LIBUSB_ERROR code on failure.
*/
int (*handle_transfer_completion)(struct usbi_transfer *itransfer);
/* Get time from specified clock. At least two clocks must be implemented
by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
Description of clocks:
USBI_CLOCK_REALTIME : clock returns time since system epoch.
USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
time (usually boot).
*/
int (*clock_gettime)(int clkid, struct timespec *tp);
#ifdef USBI_TIMERFD_AVAILABLE
/* clock ID of the clock that should be used for timerfd */
clockid_t (*get_timerfd_clockid)(void);
#endif
/* Number of bytes to reserve for per-context private backend data.
* This private data area is accessible through the "os_priv" field of
* struct libusb_context. */
size_t context_priv_size;
/* Number of bytes to reserve for per-device private backend data.
* This private data area is accessible through the "os_priv" field of
* struct libusb_device. */
size_t device_priv_size;
/* Number of bytes to reserve for per-handle private backend data.
* This private data area is accessible through the "os_priv" field of
* struct libusb_device. */
size_t device_handle_priv_size;
/* Number of bytes to reserve for per-transfer private backend data.
* This private data area is accessible by calling
* usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
*/
size_t transfer_priv_size;
};
extern const struct usbi_os_backend usbi_backend;
extern struct list_head active_contexts_list;
extern usbi_mutex_static_t active_contexts_lock;
#ifdef __cplusplus
}
#endif
#endif